Production of alcohols



(anrerer :inventor 710% Gttomeg:

F. J. METZGER PRODUCTION oF ALCoHoLs Filed Deo. 4, 1936 July 20', 1937.

Heat Excanyer Wafer lol/mp Patented July 20, Y1937 UNITED sTATl-:s

` PATENT OFFICE PRODUCTION or' ALcorroLs Floyd J. Metzger, New York, N. Y., assignor-to Air Reduction Company, Incorporated, New

York, N.l Y., a corporation of New York Application lDecember 4, 1936, Serial No. 114,285

4 claims. (ci. csc-rss) This invention relates to improvements in they synthetic production of alcohols from alkylenc alyst, in a continuous manner, the temperature required for carrying out the process in a .sat-

isfactory manner may be around 250) C. or 275V C. or even'300 C. or higher, and the dilute acid must be maintained at such high temperature and under a high pressure during the continuous carrying out of the process.

Sulfuric or phosphoric acid, if brought into contact with a lead lining at such high tempera-` tures, ywill rapidly corrode or destroy the lead lining which will not withstand the'corrosive action of such acids at such high temperatures.

I have found that the Vproductionof alcohol can be satisfactorily carried out in a lead lined apparatus at such high temperatures by providing an insulating layer of acid resistant material of suiiicient thickness between the acid and the lead lining and by cooling the lead lining so that it is maintained below the critical temperature lat which such objectionable corrosion by the acid takes place. I have found that,..in the carrying v out of such a process, using dilute sulfuric 'acid as a catalyst, the critical temperature of the lead,

up to which it can stand the action of the sulfuric. acid, is around 200 to 220 C., and that with 40 phosphoric acid, the critical temperature of the lead is about thesame, or somewhat lower 'than' this, and that, by keeping the lead lining safely.

below such critical temperature, by maintaining a regulated temperature differential between the lead :liningr and the acidin the apparatus, the acid can be readily maintained at much higher temperatures than'the critical temperature,- eg. around 250 C. or 275 C. or even 300 C. yorfhigher, without injury to the 'lead lining `during the 'carrying out of the process.

'I'he insulating layer of acid resisting material should be of suiiicient thickness to enable 4the iecessary temperaturel differential to be maintained"*'It"istnot `necessary that the acid resisting lining should be impermabletothe acid,

' vided inside of the lead lining. `lected for this lining should, of course, be reand the acid which passes through the lining, or, where the lining is made of bricks or blocks, through the joints between the bricks or blocks, or through the cement in which the bricks or blocks lare set, will come into contact with the 5 lead lining. The acid resisting lining should,

Y however', be such as to prevent circulation of the acid over the lead lining.` That is, the acid resisting lining should be of sumcient thickness to give the necessary temperature insulation and l0 enable the necessary temperature ,differential to be obtained and it should be free from cracks or openings of such nature as to permit the hot acid to circulate over the lead lining' in a manner such that it is not protected. 15-

Various types of. materials may be `used for the acid resisting insulating lining which is pro- Any material sesistant to the acid which is used, that is, to phos- 20 phoijic acid' or to sulfuric acid as the case may be, and should be a sufficiently good insulator or used in suflicient thickness to provide the necessary temperature diierential between the hot acid and the lead lining. Bricks of Pyrex glass 25 are advantageous for use with either phosphoric or sulfuric acid. These bricks are available in accurately machined form, so that they may be set in place without the use of cement with suf lilci'entlytight joints so that there is no circula- 30 tion of acid betweenthe bricks siich as might permit objectionable corrosion of the lead lining by the washing action of the circulating acid. Another material which may beiused with advantage with 4either sulfuric or phosphoric acid 35 is a variety of porcelain known in the trade as Isolantita With sulfuric acid, acid resisting brick, such as a-high grade of silica brick, set in acid resisting cement. may be usedv with fadvantage. Other suitable acid resisting lining 40 materials may also be used.

The catalytic production of ethyl alcohol by the catalytic interaction of ethylene and steam in the presence of 'hot, dilute acid 'is an exothermic reaction, which can be regulated and 45 controlled by regulating the vtemperature of the steam and ethylene entering the 'converter chamber or by neutralizing the heat of reaction by the addition of a regulated amount of vwater or by permitting any Aexcess Vof heat of reac- 50 tion to escape through the walls of the apparatus. Whatever the 'method of regulation of the temperature o1' the acid in the converter, it is necessary both to keepthis acid at a sufiicien'tly high temperature to bring about inan 5/ effective manner the conversion of the ethylene into ethyl alcohol and also to prevent undue with a lead lining and with an insulating layer of acid resisting material inside the lead lining,I

the necessary-temperature differential between thatof the acid inside the converter chamber and the lead lining should be maintained to' protect the lead lining, that is, to maintain it safely below the c'rictical temperature. The extent to which 'the lead lining can be cooled below the critical temperature will be limited by the factl that excessive cooling may cool the acid too much, and while the lead lining should be maintained at a safe margin belwjts critical temperature, it should not be maintained at such a low temperature as will interfere with the maintenance of the necessary high temperature of the acid required for the carrying out of the process.

Instead of providing all the insulation on the outside ofthe steel shell, I provide only such an amount of insulation atA this location as will avoid undue cooling of the converter as a whole and of the acid contained therein, relying on the insulating lining within the converter for a part of the heat insulation and to obtain the necessary temperature diiferential, and supplying only such added insulation outside the steel shell as is required to maintain the apparatus at a proper temperature. The thickness of the outside insulation can be readily adjusted to permit the proper amount of cooling but to avoid objectionable cooling.

The invention will be further described in connection with the apcompanyingdrawing, which shows in a conventional and diagrammatic manner an apparatus embodying theinvention and adapted for the practice of the process of the invention.

In the drawing, Fig. 1 is a flow sheet showing the different parts of an apparatus for the production of alcohols from alkylene hydrocarbons; and,

Fig. 2 is an elevation partly' in section of the converter.

In the diagrammatic arrangement of Fig. 1 the fresh supply of olen gas, such as ethylene, is -supplied under the necessary high pressure through the pipe l, past the regulating valve 2, and is admixed at 3 with the recycled ethylene, which is further admixed at withA water in proper proportion and theY ethylene and Water then passed to the heat exchanger 5, heated by the outgoing hot gases and vapors, and with resulting conversion of the water into steam and preheating of. the steam and ethylene mixture, which is further heated in the superheater 6, for example, by hot diphenyl oxide. .The preheated steam and ethylene in suitable proportions are thendpassed to the converter 8, lled part full with dilute sulfuric or phosphoric acid, which, 'at the `high temperature and pressure, acts as a catalyst to convert part of the ethylene and steam to alcohol. The admixed alcohol vapors, steam and unconverted ethylene pass from the converter 8 through the line 9 to the heat interchanger 5, where they are cooled and partly condensed, and then to the first condenser I5.

The condensed aqueous alcohol collects in the separator I6 and can be drawn off through the line Il, having pressure reducing valve I8 therein, to the storage tank I9. The `iin0ll1ll$ed vapors and ethylene pass through the line 20 to outer steel shell 30 of a construction adapted to Y withstand high pressure, e. g. of 1000 pounds per square inch or higher. Within this steel shell is the lead lining 3i; and inside this lead lining is the insulating layer of acid-resisting material 32, which may be made of Pyrex glass bricks, acid resisting brick set in acid-resisting cement, etc.

The converter chamber is shown with supports 33 at the bottom and with a bolted head 3d at the top having openings 35 and 36 therethrough for the introduction of the admixed ethylene and steam` and for the escape of the unconverted ethylene and steam and admixed alcohol vapors. A

'Ihe converter is shown as provided with a perforated distributing plate 38 below vwhich the admixed steam and ethylene enter, and suitable filling material 39, such as Raschig rings or cylinders of the same length and diameter and of `acid resisting material is shown as supported on saidperforated plate to bring about intimate contact of the ethylene and admixed steam with the body of dilute acid as they pass upwardly through the converter.

A thin layer of insulation 31 is shown on the outside of the Asteel shell, the thickness of this insulation being regulated to give the proper protection to the apparatus from undue cooling while nevertheless permitting sulcient cooling to in- `r sure maintenance of the lead lining suiiiciently below the critical temperature above referred to.

Insulation applied to the outside of the apparatus is readily accessible and may be of a character which permits increase or decrease of its amount in order to decrease the total heat loss or leak of the apparatus to a minimum while simultaneously maintaining the proper temperature gradient between the inside and outside of the container, that is, between the high temperature acid inside the converter and the lead lining adjacent the steel shell.

In the continuous production of ethyl alcohol from ethylene diierent strengths of Asulfuric or phosphoric acid can be used. With the higher temperatures, e. g., around 250 C. or higher, relatively dilute sulfuric or phosphoric acid is advantageously used, generally below 50% strength, and even down to a small percentage. With such dilute acids high temperatures, such as those referred to, are advantageous, and the present invention enables such temperatures to be advantageously employed While at the same time protecting the apparatus from leakage by a lead lining which is itself protected from corrosion by the maintenance of the temperature gradient above referred to.

The pressure maintained during the process,A

The proportions of steam and ethylene or other olen will varyldepending upon the temperature, pressure and acid concentration, these\ various factors being interdependent.

ItA will thus be seen that the present invention provides an improved method of producing alcohols by the catalytic hydration of olefins with the use of dilute sulfuric or phosphoric acid catalysts maintained at a temperature above the critical temperature which a lead lined converter can withstand while a lead lining is nevertheless used vand protected from such corrosion by the use oi insulating material and the maintenance of a temperature gradient between the hot acid and thelead lining such that the lead lining 4is maintained safely below the critical temperature.

I claim:

1. The method of producing alcohols in a continuous manner by the catalytic hydration of olens with a dilute acid catalyst ofthe class consisting of sulfuric and phosphoric acids, which comprises maintaining a body of such dilute acid catalyst, during the catalytic hydration o' the oleiins, of substantially uniform strength and under a high pressure in a high pressure converter having a lead lining, maintaining the body of dilute acid catalyst at an active catalytic temperature far above the normal boiling point of the dilute acid and above the temperature to which the lead lining can be subjected without objectionable corrosion, insulating the body of acid from the lining and maintaining the lining at a temperature below that of objectionable corrosion, and subjecting the lining to regulated cooling to aid in the maintenance of the' high temperature of the body of acid catalyst and the said temperature differential.

2. The method of producing alcohols in a con.

tinuous -manner by the catalytic hydration ci' oleilns with a dilute acid catalyst of the class consisting of sulfuric and phosphoric acids, which comprises maintaining a body oi' such dilute acidfof less than about strength under a high'pressure in a high pressure converter having a lead lining, maintaining the body of dilute acid catalyst at an active catalytic temperature in excess of about 220 C. during the catalytic lhydration of the oletlns, said temperature being farabove the normal boiling point of the dilute acid and above the temperature to which the lead lining can be subjected without objectionable corrosion, insulating the body of acid from the lining and maintaining the lining at a temperature lower than about 200 C. and below that of objectionable corrosion of the lining by the acid, and subjecting the lining to-regulated cooling to aid in the maintenance o f the high temperature of the body of acid catalyst and the said temperature dinerential.

3. The method ofsproducing alcohols in a continuous manner by the catalytic hydration oi' olens with a dilute rraciti catalyst of the class consisting of sulfuric and phosphoric acids, which .comprises maintaining a body of such dilute acid olens, of substantially uniform strength and under a high pressure in a high pressure converter having a lead lining, maintaining the body of dilute acid catalyst at an active catalytic tempnlature far above the normal boiling point of tine dilute acid and above the temperature to which the lead lining can be subjected without objectionable corrosion, insulating the body of acid from the lining and maintaining the lining at a temperature below' that of objectionable corrosion, and subjecting the lining to regulated cooling to aid in the maintenance of the high temperature of the body of acid catalyst and the said temperature differential, said regulated cooling being eiected by insulating the lining from 'the surrounding atmosphere, the nature and thickness oi said insulation being such as to maintain said temperature differential between the hot acid catalyst and the lining, and between the lining and the atmosphere during the process.

4. 'Ihe method of producing alcohols in a continuous manner by the catalytic hydration of oleiins with a dilute acid catalyst of the class consisting of sulfuric and phosphoric acids, which comprises maintaining a body of such dilute acid catalyst of substantially uniform strength under a high pressure in a high pressure converter having a metal shell adapted to withstand high pressure and a lead lining therein, maintaining the body of dilute acid, during the catalytic hydration of the olens, at an active catalytic temperature in excess of about\200 C.. said temperature being far above the normal boiling point of the dilute acid and above the temperature towhich the lining can be subjected without objectionable corrosion, insulating the body of hot acid ,from the lining and maintaining the lining at a temperature lower than about 200 C. and below that of objectionable `corrosion of the lining by the acid, and subjecting the lining to regulated cooling to aid `*in the maintenance of the high temperature of the body of acid catalyst and the said temperature differential, said regulated cooling being effected by insulating the lining from the surrounding atmosphere, the nature and thickness of said insulation being such as to maintain .said temperature differential between the hot acid catalyst and the lining, andbetween z the lining and atmosphere during the process.

- FLOYD J. BIE'IZGER.

l catalyst, during the catalytic hydration of the 

